ethyl 7-(3-chlorophenyl)-2,4-dioxo-1,5,6,7-tetrahydropyrano[2,3-d]pyrimidine-6-carboxylate

ethyl 7-(4-methoxyphenyl)-2,4-dioxo-1,5,6,7-tetrahydropyrano[2,3-d]pyrimidine-6-carboxylate

ethyl 7-(4-nitrophenyl)-2,4-dioxo-1,5,6,7-tetrahydropyrano[2,3-d]pyrimidine-6-carboxylate

ethyl 7-methyl-2,4-dioxo-7-phenyl-5,6-dihydro-1H-pyrano[2,3-d]pyrimidine-6-carboxylate

ethyl 4-oxo-7-phenyl-2-sulfanylidene-1,5,6,7-tetrahydropyrano[2,3-d]pyrimidine-6-carboxylate